No Cleanliness Not Acceptable
No-clean pastes have specific physical properties, which directly impact industry standard electronic assembly cleaning processes. This paper sets out to establish new benchmarks for cleaning no clean surface mount solder paste residues (including the most challenging latest lead free product formulations) by incorporating leading cleaning technologies, the actual impact of different spraying technologies, temperature air vs. nitrogen atmosphere, as major variables. The cleaning evaluations were conducted in a controlled application technology center while using thermally profiled reflow conditions and cleaning equipment. The response variables used were qualitative visual inspection of cleaned surfaces (i.e. white residues) as well as the solder joint appearance. This innovative approach has now provided for new solutions and will help future users to minimize their cleaning challenges.